Embodiments of the present invention relate to a robotic storage system for storing microplates carrying a plurality of sample tubes. More particular, in some embodiments, the robotic storage system comprises a freezer room having a plurality of freezing units and a first robot being capable of removing a microplate from and moving a microplate into a said freezing unit. The robot may be further capable of transferring the microplate to a processing station. The present disclosure also relates to a stacker adapter for use in a robotic storage system and a container, in some embodiments, a cardboard box, for shipping a stack of microplates used in a robotic storage system.
In clinical studies a wide variety of assays can be carried out to answer questions related to diagnosis (e.g. biomarker), treatment (e.g. efficacy of a drug) and prevention of diseases.
Large sample collections of biological samples can be established e.g. within the context of clinical studies. Such biological samples can be e.g. blood samples (whole blood, plasma, serum), urine samples, tissue samples, or samples containing cells (e.g. primary cells, stem cells), proteins, DNA, RNA (RNAi, mRNA), or antibodies. The samples are frequently used in small amounts, for example in the range of few microliters, and handled in sample tubes which are removably arranged in microplates. Such sample tubes can be advantageous since they can be sealed and thereby easily transferred between several microplates in a sealed state. Particularly, when the samples additionally are held frozen inside the sample tubes, they can efficiently be transferred from one microplate to another microplate without impairing the frozen state of the samples.
Such biological samples are typically stored at a temperature of about −80° C. in specific humidity controlled rooms. Cooling of a complete humidity controlled room for storing biological samples as described above to about −80° C. (or below) is generally feasible. However, at said temperatures standard handling devices, such as for example robots, usually do not work properly. Therefore, particularly for long-term storage of biological samples, specific −80° C. freezers are typically used.
Such freezers for long term storage of samples usually have a tight and thermally insulating door which separates the environment outside the freezer from the −80° C. interior of the freezer. In a robotic storage system, a plurality of such freezers is arranged in a −20° C. room as well as a robot for taking the samples out of the respective freezer. As mentioned above, the robot cannot be arranged in a −80° C. environment, since this simply is not economically feasible in such an environment, and in addition maintenance of the robot would be difficult then. Instead, the robot is arranged outside the freezers in the −20° C. environment where it is capable of working properly.
A robotic storage system belonging to the state of the art, e.g. Bio-Sample Store™ from REMP AG, Switzerland, comprises freezers having a temperature of about −80° C. and a freezer room having a temperature of about −20° C. The freezers are aligned on each side of a corridor of the freezer room and a robot is movable along the corridor on tracks installed on the floor in the corridor. Whenever a specific sample tube is requested, the robot opens the corresponding freezer and removes the microplate carrying the specific sample tube from a drawer of the freezer. Then, the robot removes the sample tube from this source microplate and transfers it to a destination microplate which is arranged beneath the source microplate. This step is performed by transferring the sample tube through the source microplate into the destination microplate. After tube transfer has been performed, the robot moves the source microplate back into the drawer of the freezer. Once the destination microplate has been filled with all desired sample tubes, the robot moves the destination microplate to a hand-over point.
However, this known robotic storage system has a number of disadvantages. Firstly, the temperature difference of about 60° C. between the temperature in the freezer room (−20° C.) and the temperature in the freezers (−80° C.) results in the creation of considerable amounts of ice inside the freezers and on the microplates whenever humidity enters the freezer upon accessing a microplate.
Secondly, as the robot has to fulfill all the afore-mentioned tasks (opening a freezer, removing a microplate from a drawer of the freezer, tube transfer into a destination microplate, moving the microplate back into the drawer of the freezer, further tube transfer of other sample tubes into the same destination microplate, moving of the destination microplate to a hand-over point) one after the other, it is of a very complex construction and is therefore very expensive. On the other hand, the various functions of the robot are not efficiently used.
Thirdly, as the robot is permanently arranged in the freezer room at about −20° C., maintenance work has to be performed under difficult conditions. Given these conditions, security provisions of several countries require a minimum of two workers to enter the freezer room together at the same time for performing the maintenance work.